What could potentially happen due to decreased preload from hypotension and inferior vena cava (IVC) compression in pregnancy?

Decreased preload, which refers to the reduced volume of blood returning to the heart, can lead to hypotension and is particularly relevant in the context of pregnancy. When the inferior vena cava (IVC) is compressed, often due to the weight of the gravid uterus, it impedes venous return and subsequently can cause significant drops in maternal blood pressure.

This chronic hypotension can compromise maternal and fetal circulation. If this condition escalates, it can lead to serious outcomes such as inadequate perfusion of vital organs, eventually culminating in cardiopulmonary arrest if not addressed promptly. Maternal collapse, in this case, is a life-threatening scenario where the heart ceases to function effectively due to prolonged low blood volume and pressure, leading to decreased cardiac output.

In this context, increased fetal movement and uterine hypertonicity are not direct consequences of decreased preload but rather may occur under different circumstances. An increase in maternal heart rate can occur as a compensatory mechanism to try to maintain cardiac output despite the low preload. However, it is the potential for cardiopulmonary arrest that represents the most severe risk associated with significant hypotension and IVC compression during pregnancy.